I saw this question pop up on a forum and I know every PHP developer has their own reasons, it made me think of why I initially picked PHP way back in the early 2000’s when v4.3 was king.
It all started when my family hired a web developer to create a website for their motorcycle dealership. Everyone was moving to the web, and we didn’t want to be left behind. We ended up hiring a local guy, and a few months later a new website was delivered that was built entirely with Microsoft Front-page. He sat with me for an hour or so and showed me the basics on how to update it, took his check, and then went on his merry way.
Flash forward about two months, and I was spending half my day on Front-page forums trying to figure out the tool and how to make cool things. I loved it! Eventually, though I was sick and tired of Front-page, the extensions kept breaking, and every time it was a nightmare to fix.
This led me to a crossroads. I wanted to remake the site so it was dynamic and so we could quickly add new inventory. The two languages I heard was best for this was either ASP or PHP. To a newbie, they both seemed like greek, but PHP hosting was cheaper, so that is the direction I went.
With the language chosen, I started reading everything I could and tinkering, but it didn’t “click” I struggled more than I’d like admin with understanding the relationship between PHP, MySQL, and Apache. Keep in mind back then I had zero tech friends and nobody local I could even ask. It was trial and error from tutorials and forums.
What I ended up realizing is the part I struggled with was that I couldn’t actually see the relationship between all these tools. Around this time I tried Dreamweaver, and it helped tremendously because it was all basically integrated into a single app.
As I compare then to today the training material now is leaps and bounds better than we what we had. Yes, web development is way more complicated today, but everything from tutorials, to training videos, to even open source apps. Everything is better explained than back then.
So to finally answer the question, “What makes PHP popular?”, For me, it was cheaper hosting, and once I grasped the basics, I never left the community. If it works, embrace it.